[Role of LFA-1/ICAM-1-dependent cell adhesion in CD40-mediated inhibition of anti-IgM antibody-induced B-cell death].

To investigate the role of CD40-transduced signals in surface IgM (sIgM)-mediated B cell death, we used a human B cell line (DND-39). Crosslinking of sIgM by Abs induced DND-39 cell death (apoptosis). Anti-CD40 Abs induced homotypic adhesion of DND-39 cells and rescued them from anti-IgM Ab-induced apoptosis. Treatment with Abs against LFA-1/ICAM-1 inhibited not only the homotypic adhesion but also the inhibition of anti-IgM Ab-induced apoptosis by anti-CD40 Ab. Otherwise, CD11a antisense decreased the inhibitory effect of anti-CD40 Ab on anti-IgM Ab-induced apoptosis. The data show that LFA-1/ICAM-1-dependent cell adhesion induced by signaling through CD40 plays an important role in the inhibition of anti-IgM Ab-induced apoptosis of DND-39 cells.